Safety device for elevators.



F. W. MAYFIELD.

SAFETY DEVICE FOR ELEVATORS.

APPLICATION FILED DEC. II. $915.

1 1 96,269.. Patented Aug. 29, 1916.

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SAFETY DEVICE FOR ELEVATORS.

Application filed December 11, 1915.

T 0 all whom it may concern:

Be it known that I, FRANK W. MAYFIELD, a citizen of the United States, residing at Bloomington, in the county of Monroe and State of Indiana, have invented certain new and useful Improvements in Safety Devices for Elevators, of which the following is a speci fication.

This invention relates to, the class of safety devices for elevators which include a governor mechanism associated with braking means in order to set the latter when the elevator car exceeds a predetermined speed in its descent.

As a principal object, this invention contemplates the provision of means automatically operable to effect the stoppage of the car when descending at an unsafe speed, without requiring any attention from the operator of the car except for resetting purposes after the stop has been achieved.

More specifically, it is an object of this invention to provide brake means adapted to be revolved when set into action and to provide a shaft equipped with means for operating the brake means adapted to be set in motion by the action of a governor attached directly to the same shaft.

Still more specifically, it is an object of this invention to provide a brake controlling shaft having a governor attached to one extremity and means for driving the. brakes into the set position at the other extremity, there being furnished intermediately positioning means to control the brake setting means and actuable by a governor through a trip mechanism, the latter being provided with connections whereby the operator of. 1nech= the car can readily restore said trip anism to normal position.

The above and additional objects which will be hereinafter more specifically treated.

are accomplished by such means as are illustrated in the accompanying drawings, de-.

scribed in the following specification and then more particularly pointed out in the claims which are appended hereto and form a part of this application.

With reference to the drawings, wherein there is illustrated the preferred embodiment of this invention as it is reduced to practice, and throughout the several views of which like characters of reference designate similar parts, Figure 1 is a bottom plan Specification of Letters Patent.

Patented Au 29, 1916..

Serial No. 66,320.

view of the safety device as provided upon an elevator car; Fig. 2 is a side elevational view of the subject-matter of Fig. 1; Fig. 3 is a sectional View oil the line 3-3 of Fig. 2; Fig. 4 is a sectional view through the brake means at right angles to Fig. 3; Fig. 5 is a view in section taken on the plane indicated by the line 55 of Fig. 1; Fig. 6 is an elevational detail of the subject-matter of Fig. 5, and Fig. 7 is a detail showing on an enlarged scale the disengageable driving means in operative position.

The safety device of the present invention has been shown as applicable to that type of elevator car which is vertically movable between a pair of upright guides, although it will be obvious that adaptations of the device will render its use feasible upon any other type of elevator. The device as a whole is placed upon the bottom of the elevator car 10, such car being movable between the upright guides 11 at opposite sides of the elevator shaft, through the medium of the head blocks 12 of the usual character.

Each of the head blocks 12 is provided with a recess 13 in which there is slidable a brake shoe 14 in such manner as to be operable directly upon the upright 11 as will be clear from an inspection of Fig. 3. Each of the shoes 14 is provided with a recess in which the headed extremity of an operating bolt 15 is seated, plates 16 serving to maintain the bolt in its proper position with respect to the brake shoes and securing means 17 passingthrough each shoe to secure the plates. The bolt 15 extends through the head block 12 within which it has a screw threaded seat and has keyed upon its projecting extremity a beveled pinion 18, as is the case for each head block 12.

A. shaft 19 extends across the bottom of the elevator car 10 and is supported in brackets. 20 secured to the opposite head blocks. At the extremities of this shaft are carried the beveled pinions 21 for respective engagement with opposite pinions 18. R0- tation of this shaft will serve to set each of the brake shoes 14 into frictional braking engagement with the upright guides 11, by causing a rotation of the operating bolts 15 through the threaded seats provided in each head block.

Journaled in suitable bearings 22 supported by framing 23 fastened to the floor of the elevator car to connect the head jacent bearing 22 while the opposite side carries a link 30 forminga connection to be 7 hereinafter more fully set forth. Brackets gear 25, a turn the movement of the car.

31 extend from suitable points of the framing 23 to support-the shaft 19 and a pair of beveled pinions 32 and 33, respectively keyed and'loose upon the shaft'19, are carried in juxtaposition to. these brackets in order to mesh with the sliding gear 25 formlng thereby a disengageable driving means for actuating the brake shoes. 7 I

At the opposite extremity of the shaft 24 is a fixed collar 34 to which is linked one end of a governor 35 of the usual form, the opposite end being connected to a slidable collar 36 which is splined upon the shaft 24 to accommodate centrifugal motion of the governor balls. At a certain point on the framing 23 is pivoted the bell crank lever 37 and this lever is connected by rods 38 with the link 30 for actuating the sliding buckle .39 or similar device being employed to permit a linear adjustability of the rods 38. A spring 40 engages the bell crank 37 in order to actuate the gear 25 into meshing with the gears 32 and 33 but a catch lever 41 which is formed with a yoke 42 for engagement with the sliding governor collar 36 carries a projection 43 adapted to rest in a bracket arm 44 of the bell crank lever for the purpose of preventing movement of this lever in response to the spring 40. Spring means 45 also acts upon the lever 41 to normally maintain it in looking engagement with the bell crank lever, unless positively actuated by means of movement on the part of the collar 36. jThe shaft 24 is adapted to be driven at all times when the elevator car 10 is in motion and to be driven at speeds proportionate to This is accomplished through the employment of a rack bar 46 which is secured to one of the upright guides 11 and has meshing therewith a gear 47 mounted at theextremity of the shaft 48 which is journaled in brackets 49 carried by the head block 12 riding upon the mentioned upright. Miter gears 50 carried re spectively at the extremity of the shaft 48 and intermediately of the shaft 24 provide driving connections between the shafts at all times. A flexible connection 51 is secured to the free extremity of the bell crank 37 and extends through an aperture 52 in the floor of the car 10 in order to permit the opertionately the speed of the shaft 24, has

reached a predetermined point which is unsafe to the passengers of the car, the governor 35' will pull the collar 36 toward the extremity of theshaft until the catch lever 41 1s so actuated as to release the bell crank 37 which will then be caused by the impulse of the spring 40 and through the connections 38 to slide the gear 25 into engagement with the gears 32 and 33 respectively fast and loose upon the shaft 19. The gear 32 will then transmit rotation of the shaft 24 to the shaft 19 while the gear 33 is mainly employed to act as a guide for the sliding gear. Rotation of the shaft 19 will cause a consequent rotation, as previously explained of the operating bolts 15 for each brake shoe, these latter being then jammed into a frictionally braking engagement with the upright guides 11, it being noted that the bolts 15 are provided with oppositely threaded seats within the head blocks in order that both may be operated by the same rotational movement of the shaft 19.

To reset the device after a stop has been effected by the jamming action of the brake shoes 14 against the guides 11, the operator raises the car until the brake shoes have been 00 released and then exerts a pull on the flexible connection 51 such that the bell crank lever will be forced back into engagement with the locking extension 43 of the catch lever 41, the governor, of course, having 105 ceased to control the lever 41 and the spring 45 having returned to its normal position permitting engagement between the extension 43 and the bracket 44.

While in the foregoing, however, there 110 has thus been illustrated in the drawings and described in the specification such combination and arrangement of elements as constitute the preferred embodiment of this invention, it is desired to emphasize the fact 115 that such minor changes in the matters of proportion and degree may be made in later adaptations of this device as shall not alter the spirit of the invention as defined in the appended claims.

What is claimed is 1. The combination with an elevator car and fixed upright guides in the elevator shaft, of head blocks carried by said car and slidable on said guides, brake shoes op- 125 erable through the head blocks for engagement with the guides, oppositely rotatable operating means for the brake shoes, a single operating shaft for said operating means, a cross shaft, disengageable driving 13D means between said cross shaft and the first the head blocks for'engagement with the guides, oppositely rotatable operating means for the brake shoes, a single operating shaft for said operating means, a cross shaft, a

governor carried by the cross shaft, disengageable driving means between the cross shaft and the first-mentioned shaft, resiliently actuated means for causing when released operative engagement of said driving means, and a trip mechanism controlled by the governor for releasing said actuated means.

3. In a safety attachment for elevator cars, the combination with an elevator car, fixed vertical guides therefor, and a vertical rack on one of said guides, of blocks slidably engaging the guides, a brake shoe slidable within each block for frictionally engaging the guides, a bolt threaded in each block to actuate the brake-shoe, a shaft to operate the bolts, a second shaft, a gearwheel thereon in engagement with said rack to rotate said shaft by the movement of the car, a control shaft operated by said second shaft, disengageable driving means between the control shaft and the first-mentioned shaft, resiliently actuated means for causing when released operative engagement of said driving means, and a trip mechanism controlled by the governor for releasing said resiliently actuated means when said elevator exceeds a predetermined speed.

4. In a safety attachment for elevator cars, the combination with an elevator car and upright guides therefor, of blocks slidably engaging the guides, brake shoes slidable in each block for frictional engagement with the uprights, a bolt threaded in each block, said bolts when rotated actuating the brake shoes in unison, a shaft having means thereon to rotate said bolts, a control shaft rotatable by the movement of the elevator car, governor means operable at one end of said controlling shaft, a sliding gear at the other end of said shaft forming disengaging means for imparting motion to the bolt rotating shaft, intermediate means for causing engagement of said disengageable driving means, and a trip mechanism controlled by the governor for causing the operation of said intermediate means.

5. The combination with an elevator car, and upright guides, of head blocks slidable upon the guides, brake shoes operable through the blocks to frictionally engage the guides, oppositely rotatable bolts controlling movement of the shoes, a shaft for rotating the bolts, a cross shaft, a governor carried at one end ofthe cross shaft, a sliding gear carried at the other end of the cross shaft for a governor-determined engagement with the first said shaft, and lever means between the governor and the sliding gear and resiliently impelled to cause an operation of the first said shaft.

6. The combination with an elevator car and upright guides, of head blocks slidable upon the guides, brake shoes operable through the blocks to frictionally engage the guides, oppositely rotatable bolts controlling movement of the shoes, a shaft for rotating the bolts and having a gear wheel thereon, a cross shaft, a governor carried at one end of the cross shaft, a sliding gear carried at the other end of the cross shaft for a governor-determined engagement with the gear of said first shaft, lever means connected to said sliding gear and resiliently impelled to cause an engagement of said gears and the operation of said first shaft, and a' catch lever controlled in movement by the governor that normally prevents operation of the lever means until released by said governor.

7. The combination with an elevator car, and upright guides, of head blocks slidable upon the guides, brake shoes operable through the blocks to frictionally engage the guides, oppositely rotatable bolts controlling movement of the shoes, a shaft for rotating the bolts, a gear on said shaft, a cross shaft, a governor carried at one end of the cross shaft, a sliding gear carried at the other end of the cross shaft for a governor-determined engagement with the gear on said shaft, lever means connected to the sliding gear and resiliently impelled to cause an engagement of said gears and the operation of the first shaft, a catch lever controlled in movement by the governor that normally prevents operation of the lever means until released by said governor, and means within the car attached to said lever means to reset said lever means and the catch lever after a stoppage of the car.

8. The combination with an elevator car, and a pair of guides therefor, of head blocks slidable on the guides, brake shoes slidable within each block for operation upon the guides, a shaft for driving both of the brake shoes into set position, a parallel shaft adapted to be driven proportionately to the movement of the car, a cross shaft driven by the said second shaft, disengageable driving means between the first-named shaft and the cross shaft, resiliently actuated means for causing the engagement of said driving means, and governor controlled means for releasing said resiliently actuated means.

9. The combination with an elevator car and upright guides therefor, of head blocks V engaging the guides, brake shoes slidable in the blocks for frictionally engaging the guides, an operating shaft for the brake shoes," a parallel shaft, rack means carried byone of the guides for operating the f parallel shaft,'. a cross shaft constantly I driven fromthe parallel shaft, a governor carried at one extremity of the crossshaft, disengageable driving means for the brake V shoe operating shafton the other extremity of said cross shaft, resiliently actuated means for causing the engagement of said driving means, and a catch'lever normally restraining said actuated means controlled shoes, a parallel shaft, rack means carried by one of the guides for operating the parallel shaft, a cross shaft constantly driven from the parallel shaft, a governor carried at one extremity of the cross shaft, disengageable driving means for the brake shoe operating shaft on the other extremity of said cross shaft, a resiliently actuated bellcrank lever for causing when released the engagement of said driving means, a catch lever for restraining the operation of said bell crank lever and controlled by said governor, and means on the car for resetting said bell-crank lever after actuation of the same.

In testimony whereof I aflix my signature in presence of two witnesses.

FRANK W. MAYFIELD. Witnesses:

PHILIP C. BILLMEYER, JOHN MURPHY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

7 Washington, D. G. 

